Published: June 6, 2023 By

Balaji Rajagopalan grew up in a small railroad town near Hyderabad, India, in a home without running water. At night, the sound of water would often awaken him, prompting him to rush with cooking pots to collect water spurting from a pipe in the backyard. During the dry season, the pipe often ran dry, forcing him and his neighbors to queue up to manually pump a single bucket of groundwater.

Now a CU Boulder professor of civil engineering and an expert in hydrology, climatology and water resources, Rajagopalan was recently honored with a Fulbright-Kalam Climate Fellowship and an opportunity to make a difference in his native country. 

His Fulbright work in India centers around developing monsoon forecasting models to aid residents in flood preparedness; exploring the intricate interplay between monsoonal climate and public health; and unraveling the monsoon variability over a timeframe of 5,000 to 10,000 years, along with its role in the peopling of the Indian subcontinent. 

“I want to give back,” said Rajagopalan, a first-generation college graduate. “The areas I am working on — climate and water — are central here.”

Starting in August, he will spend four to six months over a two-year period at four host institutions — the Indian Institute of Technology, Hyderabad, as well as Gandhinagar, Roorkee and Ashoka Universities. He plans to foster collaborations among these and other institutions in India and facilitate research exchanges between the universities in India and CU Boulder. 

Having served as the chair of CU Boulder’s Department of Civil, Environmental and Architectural Engineering, Rajagopalan is also excited to observe how some of India’s top institutions teach civil engineering and to mentor and engage with early career scientists, including students and faculty. 

Monsoon clouds arriving at Port Blair
Monsoon clouds arriving at Port Blair, Andaman, India. Photo Credit: RIDHVAN SHARMA

Fascination of the Monsoon

For more than 20 years, Rajagopalan has dedicated his research to understanding and modeling the variability and predictability of flow in the Colorado River and the Indian monsoon.

He wonders aloud why the amount of water in the Colorado River has been declining for more than two decades and whether the decline is random or hints at a more systematic global climate pattern. He raises the same question about annual fluctuations in the Indian monsoon rainfall.

“Those questions fascinate me,” he said. “Both the Colorado River and the Indian monsoon are the lifeblood of the societies that depend on them.”

He recalls that in the late 19th century, during the British colonial rule of India, the monsoon mercilessly failed, leading to a devastating famine that claimed the lives of millions. In the wake of this catastrophic event, the British colonials established the Indian meteorological department to study the monsoon. Since then, there’s been more than a century of studies to understand this climatic phenomenon.

“But still, there are many more questions,” he says. “That’s the fascination of the monsoon.” 

Traffic in flooded streets in Mumbai
Flooding in Mumbai, India, 2017. Photo credit Paasikivi

Flood Forecasting  

Rajagopalan points out a challenge specific to India: During the monsoon months of June, July and August, precipitation falls as water rather than being stored as snow, as happens in Colorado. Without sufficient infrastructure to store and manage the excess water, much of it will flood the landscape and drain into the adjoining seas, he says.

He emphasizes the pressing need for improving flood forecasting in India, given the significant percentage of the population that lives near rivers.

Reliable forecasts would enable disaster managers to make well-informed decisions regarding public evacuations. Planning agencies could prepare in advance if they knew whether the upcoming season would bring above-average rainfall. Similarly, reservoir managers need that information before the monsoon season begins to anticipate the volume of water they may collect and whether they need to open gates  early to create additional capacity. 

At the seasonal time scale, the significance of an accurate monsoon rainfall forecast has broad implications. A forecast indicating a below-normal summer monsoon season can exert pressure on agriculture commodities, resulting in reduced spending capacity for individuals. Farmers rely on these forecasts to make informed decisions regarding agriculture, either by cultivating more drought-resistant crops or by irrigating.

Rajagopalan also highlights the importance of data modeling and understanding the underlying physics behind floods and droughts to develop effective forecasting tools.

“Developing predictive tools is of huge importance for anywhere, but especially for India as the monsoon rainfall drives agriculture, water resources, ecology and public health,” he says. “The monsoon threads through the entire socio-economic fabric.” 

Public Health 

“Everything is connected to the monsoon in some way,” Rajagopalan said.

India, in particular, remains highly vulnerable to the monsoon’s variability, and the impact extends beyond floods or droughts. The monsoons also affect water quality, public health, agricultural output and even the Indian stock market, he says.

Weaker rainfall directly impacts the country’s GDP, given that at least 50 percent of the population resides in villages heavily reliant on agriculture. Crop failures often drive rural residents to migrate to urban areas in search of employment, placing sudden strain on urban resources. This has an impact on nutrition, poverty and public health, he says.

During his research, Rajagopalan will delve into the profound impact of monsoons on public health. Monsoonal rains create stagnant water in ponds, providing ideal breeding grounds for malaria and dengue in disease-carrying mosquitoes. Additionally, poor water quality during this period contributes to illnesses like diarrhea. 

“There is a direct link between monsoon rainfall and public health, and that is a whole new and important area to climate connection, " he said.

Monsoons over time

The third aspect of Rajagopalan’s research involves studying the monsoon’s variability across the current geological epoch, known as the Holocene period. Gaining insight into the monsoon’s fluctuation throughout this 5,000- to 10,000-year time period can unlock the secrets behind the rise and fall of societies, and human migration, Rajagopalan said.

Civilizations typically flourished during robust monsoons and declined when the monsoons became weaker. Combining statistical methods with contemporary and ocean sediment core data, his research aims to reconstruct the variability of climate and vegetation over Indian subcontinent and Eurasia during the Holocene. This will be used to understand the role of climate in the migration of societies during this period. 

“People move for all kinds of reasons, but often climate tends to be the catalyst, even in contemporary times,” he said. “Even through civil wars, people tend to stay. The natural human tendency is to live where one grew up and among familiar surroundings.”